Questions tagged [functions]
Questions about the use of built-in Mathematica functions, including pure functions.
3,693
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Change the function-defined solution domain to fit NDSolve original Interpellation domain
Given a system of coupled non-linear equations, I used NDSolve to solve it in the domain of:
$$ -10^{50} \le r \le 10^{50} $$
...
0
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1
answer
36
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Creating function with array input with desired coefficient and evaluate it
I had asked the same question before here Creating a list of functions with desired coefficients
but did not get the desired answer, may be I was not clear in my question.
I have defined this function ...
- 219
2
votes
2
answers
106
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Simplify inverse of function
This would be a noob question, but I need help simplifying the inverse of an expression
...
- 25
2
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1
answer
88
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Creating a list of functions with desired coefficients
I have defined this function to results some list of functions, however its not returning what I want
...
- 219
4
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3
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364
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3
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1
answer
125
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Pattern matching vs. condition in a function
I'm trying to learn stuff from pattern matching but I found sometimes pattern matching does not work as I expected. Could anyone explain why the below outputs are not same? Thank you.
And could anyone ...
- 31
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49
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NyquistPlot creates misleading connections with some plot range
This Nyquist plot depicts a plot range aiming to cover all crucial curve characteristics.
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- 495
2
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2
answers
123
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Can I write a function that describes a hysteron?
Is there a way to write a "function", or as the answer below refers it better as a memory, that has the following output:
k=0 if the last time x was outside the range (a,b), it was x<a. ...
- 197
0
votes
2
answers
73
views
Same code behaves differently as a pure function and a function, and insider another function
I have a rule-transformer that takes a list of rules (and a list generator = {σ[z], σ[-1], σ[1]})
...
- 513
2
votes
2
answers
89
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Plotting root locus - how to display 'k' values on the curve?
I'm trying to plot the root locus for the function below. Is there any way to make it display the value of 'k' when I move the cursor along the curve, similar to a tooltip?
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- 495
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31
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Defining a function for FunctionCompile[]
Lets say that I have the definition EQN4 that is determined from some calculation. If I run it in a cell, I get the following output:
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- 23
2
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3
answers
619
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How to draw an image similar to a periodic function (f [x+1]=2 f [x])?
The definition domain of function f [x] is R, satisfying that f[x+1]=2f[x],
and when x belongs to (0, 1], f [x]=x(x-1).
If for any x belongs to (-[Infinity], m], there is f [x]>=-8/9, find the ...
- 2,879
2
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1
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51
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Is it possible to ask Mathematica to give/find this largest (absolute value) argument of $\cosh$ in the expression?
I have the expression exp in terms of Cosh functions:
...
- 137
4
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6
answers
511
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Stopping mathematica from rearranging elements in a list
I have the following list
set1={-(1/x), -(1/x) + x/2 - 2 Log[x] - Log[x]/x, 1}
How when I am doing
Complement[set1, {-1/x}]
...
- 301
2
votes
3
answers
69
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Define function to test arguments and set value to 0 (application 0 Log [0] = 0)
I have an expression that has the form
f1[a, b, c] Log[ f2[a, b, c] ]
Now if f1[a,b,c] and ...
- 977
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1
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64
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To draw a function within an interval [closed]
I need to draw this function: z=f(x), where z=tanh(y) and y=sin(x), within a range of x(-2Pi,2Pi)?
Should I use "Plot" function or some other built-in functions?
Thank you
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51
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How to make a function that returns a function?
I have this function that returns another function Hs but the only way to use the function is to use Hs[t][[1]]. Is this going to slow down my code and is there a way to write this so that I can ...
- 83
3
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1
answer
120
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How can I zoom in on a specific region?
I made this plot with Mathematica but it's hard to see the region around the cirtial point -1 + 0j.
Is there any way to zoom the region?
...
- 495
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1
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76
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Trying to plot the Fourier transform solution to the heat equation on Mathematica [closed]
I have gotten the solution of the heat equation as
where f(y) is the initial heat distribution which I have been given as f(x) = e^([Sigma]x^2).
I am supposed to plot this at the value of sigma 1, 2 ...
- 1
1
vote
2
answers
70
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Listable (on certain level) custom function
I wish to make custom listable function (for 2D points) with the next behaviour:
...
- 1,187
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3
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188
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1
vote
3
answers
137
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Finding the minimum
I am trying to find the minimum R and its corresponding k, but for some reason (which I am not able to figure it out) I am getting an error that the function value is not a real number at k=1.
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- 379
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1
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71
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How to make a polynomial output be used as function for input?
I basically made a code interpolating a set of data that gives me the polynomial for the interpolation. Here's the sample interpolation I did.
...
- 43
2
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1
answer
85
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How to create a plot like this one? I think I am having issues with implementing a logarithmic axis
I am having trouble creating a type of contour plot. I have an example of what I am trying to make which is this:
and this:
I know that for the first example above, the plot was not all made in the ...
- 21
1
vote
2
answers
140
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Making the timestep of Euler method integration a variable
I am fairly new to Mathematica, and I've been trying to implement the Euler method of integration for a fluid velocity field. I can't work out how to make the timestep a variable of my Euler method ...
- 13
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1
answer
45
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Cross function not working for time dependent variables [closed]
I have two 1x3 matrices both containing time derivatives:
OwC = {{a'[t]}, {b'[t]+c'[t]}, {0}}
EwB= {{0},{b'[t]},{0}}
But when I do Cross[OwC,EwB]
I get: Cross::nonn1: The arguments are expected to be ...
- 3
0
votes
1
answer
78
views
How can I apply Residue in a functional-style way? [closed]
Let me suppose that I have got some expression, for example
f_{1}(x)+f_{2}(x)
and also a list of a form:
{1,2}
How can I apply ...
- 69
0
votes
0
answers
25
views
Adding constrains in a SYM function "Classicalsymmetries"
Please help me add constrains on my code. The function runs perfectly fine without the constrains but it gives me 7 cases and I only need one where all the constrains I have hold.
This is the code ...
- 1
1
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1
answer
116
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How to invert this function when the argument e is small?
I need to find an analytical solution the following equation for e in terms of n and p
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- 414
1
vote
1
answer
74
views
Finding out derivative of variables from an expression
I have the following expression
gh=(G^(0,0,1))[0,1,x]+G[1,x];
Where G^(0,0,1)[0,1,x]=D[G[0,1,x],x]. This is a model expression. ...
- 301
1
vote
1
answer
61
views
Replace rule inside mathematical operations
This is probably very trivial question. I want to replace D[G[0,2,1,x],x] where $D(0,2,1,x)$ is anything but the number of arguments may change keeping $x$ fixed, ...
- 301
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vote
2
answers
252
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How to interpolate an implicit function?
chi(t) is implicit function. The implicit function can be plotted by ContourPlot.
Is it possible to obtain chi(t) explicitly using function interpolation?
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- 1,753
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108
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Why ResidueSum returns 2 different values?
I want to calculate the sum of the residues of the function
$$ \frac{\sin(\theta)\tanh(\alpha x)}{-\cos(2xL)+\cos(\theta)}, $$ for $|x| \leq1$. The function has singularities at the points $x_n^\pm = \...
- 11
1
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2
answers
133
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How to calculate the depth of the lake in mathematica?
I want to calculate mean depth of Goose lake (mean depth=4.6 m), I use bellow command for this operation, But this command is not automatic and we have to create the coordinates manually, and on the ...
- 159
1
vote
1
answer
58
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Keywords included in most sentences in a paragraph?
I created a few functions that will retrieve some text from certain medical articles. However, not all articles are useful or even match the keywords I provide. Is there a way to "grade" ...
- 159
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3
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117
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4
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2
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565
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How to calculate equivalent resistance for a network of same-value resistors?
Let's assume I have n identical resistors. I can connect them either in series or in parallel (let's disregard bridge connections for now). Now, I want to list all ...
- 2,411
1
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1
answer
60
views
How to remove terms with negligible constant from expression? [closed]
I'm working on a Notebook that requires the integration of multiple expressions (sometimes numeric, sometimes analytic). These expressions are normally of the form:
...
3
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0
answers
120
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How to estimate Lake area and volume in Mathematica?
I have a satellite image of the lake and I want to estimate its area and volume.
Actual volume:1.49*10e8 m^3
Actual Area:36.9 km^2
I did the following command to find the volume, but it is not very ...
- 159
2
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1
answer
221
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Is there an easy way to hide output function arguments?
I'm working with a bunch of funtions with multiple aguments, say f[x,y,z], g[x,y,z], etc. I want to do operations with them like derivatives and products, and I want to read the result easily, without ...
0
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0
answers
72
views
How do we convert the minimum of two values into its actual result?
I am writing a code in Mathematica where the entries of the matrix depends on the minimum function, which is a function of the position in the matrix. However, when I compile it, the entries appear as ...
- 109
2
votes
1
answer
117
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Visualizing the zeros of a function of three variables
I have a function f[x_, y_, z_] := (x - y) (z^2 - x*y) of three variables x, y and ...
- 471
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0
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59
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Automatic evaluation of a function for variable values defined from different data tables in the attachments
I want to evaluate a function whose variable values are defined in different data files. I want to know that how can I write code such that when the function's evaluation is exhausted for one table, ...
- 331
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0
answers
33
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Separate definition of custom options and passed options in function definition
Why do these codes do not work?
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- 9,568
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0
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57
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How to extract shape from image in the Mathematica?
I have some satellite images for the lakes. How to extract the shape of the lake with maximum accuracy from the image?
- 159
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2
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112
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How to determine the shape of real quadric surfaces? Use discriminants?
Let $a x^2+2 b x y+c y^2+2 d x+2 e y+f=0$ be the implicit equation that defines
a conic section , where $a,b,c,d,e,f$ are real numbers.
I have known from wikipedia how to use 2 discriminants to ...
- 857
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71
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How can I calculate P-Value for a custom distribution?
I used DistributionFitTest but it works only with a defined distribution.
This is the distribution that I used:
...
- 59
1
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2
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105
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Are these tacit functions? [closed]
I am new to Mathematica and am reading the primer document by Peter Young. Early on, before even introducing functions, he introduces constructions like
...
- 111
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79
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1
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2
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128
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How to do edge detection in Mathematica?
I have some pictures of water level and I want to do edge detection, I used the following command, but this command is vertical edge detection and I want horizontal edge detection and water level. ...
- 159